extern crate std;

use crate::server::{BACKSPACE, Console, TerminalServer};
use server_framework::Server;
use std::vec;
use std::vec::Vec;
use types::bounded::CapSlot;
use types::log::{text_of, text_words};
use types::terminal::{CTRL_C, KEYS_BIT, TIMER_BIT};

#[derive(Default)]
struct Fake {
    keys: Vec<u8>,
    /// Typed while nobody reads a line.
    typed: Vec<u8>,
    flushes: usize,
    timers: usize,
    focus_taken: usize,
    interrupted: Vec<CapSlot>,
}

impl Console for Fake {
    fn draw_row(&mut self, _row: usize, _text: &[u8]) {}
    fn draw_cursor(&mut self, _col: usize, _row: usize, _under: u8) {}
    fn flush(&mut self) {
        self.flushes += 1;
    }
    fn flush_later(&mut self) {
        self.timers += 1;
    }
    fn next_key(&mut self) -> u8 {
        self.keys.remove(0)
    }
    fn poll_key(&mut self) -> Option<u8> {
        (!self.typed.is_empty()).then(|| self.typed.remove(0))
    }
    fn take_focus(&mut self) {
        self.focus_taken += 1;
    }
    fn interrupt(&mut self, notification: CapSlot) {
        self.interrupted.push(notification);
    }
}

fn term(keys: &[u8]) -> TerminalServer<Fake> {
    TerminalServer::new(Fake { keys: keys.to_vec(), ..Fake::default() }, 40, 10)
}

fn read(t: &mut TerminalServer<Fake>) -> Vec<u8> {
    let (words, _) = t.handle_call(1, [types::terminal::READ, 0, 0, 0], None);
    let (bytes, len) = text_of(words).unwrap();
    bytes[..len].to_vec()
}

#[test]
fn writes_land_on_the_grid_and_flush_once_per_burst() {
    let mut t = term(&[]);
    let before = t.console().flushes;
    for chunk in [&b"hello "[..], b"world"] {
        t.handle_call(1, text_words(chunk), None);
    }
    assert_eq!(&t.grid().row(0)[..11], b"hello world");
    assert_eq!((t.console().timers, t.console().flushes), (1, before));
    t.signal(TIMER_BIT);
    assert_eq!(t.console().flushes, before + 1);
}

#[test]
fn a_read_returns_the_edited_line_in_chunks() {
    let mut keys = b"ls -lx".to_vec();
    keys.push(BACKSPACE);
    keys.extend_from_slice(b"a /home/someone/very/long\n");
    let mut t = term(&keys);
    let mut line = read(&mut t);
    while line.last() != Some(&b'\n') {
        line.extend(read(&mut t));
    }
    assert_eq!(line, b"ls -la /home/someone/very/long\n");
    assert_eq!(&t.grid().row(0)[..6], b"ls -la");
}

#[test]
fn backspace_on_an_empty_line_does_nothing() {
    let mut t = term(&[BACKSPACE, b'x', b'\n']);
    assert_eq!(read(&mut t), b"x\n");
}

fn line_of(t: &mut TerminalServer<Fake>) -> Vec<u8> {
    let mut line = read(t);
    while line.last() != Some(&b'\n') {
        line.extend(read(t));
    }
    line
}

fn on_interrupt(t: &mut TerminalServer<Fake>, slot: u8) -> usize {
    t.handle_call(1, [types::terminal::ON_INTERRUPT, 0, 0, 0], CapSlot::new(slot)).0[0]
}

#[test]
fn ctrl_c_while_a_program_runs_interrupts_it() {
    let mut t = term(&[]);
    assert_eq!(on_interrupt(&mut t, 7), 0);
    t.console_mut_for_test().typed = vec![b'x', CTRL_C];
    t.signal(KEYS_BIT);
    assert_eq!(t.console().interrupted, [CapSlot::new(7).unwrap()]);
    assert_eq!(&t.grid().row(0)[..2], b"^C");
}

#[test]
fn only_the_first_interrupt_notification_is_taken() {
    let mut t = term(&[]);
    assert_eq!(on_interrupt(&mut t, 7), 0);
    assert_ne!(on_interrupt(&mut t, 8), 0);
    t.console_mut_for_test().typed = vec![CTRL_C];
    t.signal(KEYS_BIT);
    assert_eq!(t.console().interrupted, [CapSlot::new(7).unwrap()]);
}

#[test]
fn keys_typed_ahead_start_the_next_line() {
    let mut t = term(b"s\n");
    t.console_mut_for_test().typed = b"l".to_vec();
    t.signal(KEYS_BIT);
    assert!(t.console().interrupted.is_empty());
    assert_eq!(line_of(&mut t), b"ls\n");
}

#[test]
fn ctrl_c_drops_the_line_being_typed() {
    let mut t = term(&[b'r', b'm', CTRL_C, b'l', b's', b'\n']);
    assert_eq!(on_interrupt(&mut t, 7), 0);
    assert_eq!(line_of(&mut t), b"\n");
    assert!(t.console().interrupted.is_empty(), "nothing runs to interrupt");
    assert_eq!(line_of(&mut t), b"ls\n");
}

#[test]
fn redraw_takes_focus_back_and_paints_every_row() {
    let mut t = term(&[]);
    t.handle_call(1, text_words(b"hi"), None);
    t.handle_call(1, [types::terminal::REDRAW, 0, 0, 0], None);
    assert_eq!(t.console().focus_taken, 1);
    assert_eq!(&t.grid().row(0)[..2], b"hi");
}